A. Field of the Invention
The present invention generally relates to methods and compositions useful for minimizing pore size or the appearance thereof.
B. Description of Related Art
Mammalian skin is characterized by thousands of pores which function as openings for sebaceous (oil-producing) and sudoriferous (sweat-producing) glands and hair follicles. Pores generally serve as openings for the secretion of glandular products such as sebum, and orifices for externally applied substances, including lotions, creams, and cosmetics. Skin pores are large and numerous on the face and scalp, areas of maximum exposure. For facial areas, the density ranges from 400 to 800 pores/cm2, compared with about 50 pores/cm2 on the arms and legs. The forehead, nose, and nasolabial folds are the areas of highest pore concentration.
Pores have a defined size which is susceptible to measurement. Pore size is largely determined by genetic, environmental, and physiological factors. Visible pore diameter is often proportional to the size of subcutaneous sebaceous glands, and increased pore size is frequently associated with hyperactive sebaceous glands, including increased glandular activity and higher sebum production that occurs in adolescence, and with debris accumulation such as that observed in aging, when sebum production slows sufficiently to inhibit the constant stratum corneum shedding of normal youthful skin. Hyperactive sebaceous glands generate larger amounts of sebum which expands the pilary canal and dilates pore diameter to accommodate greater internal pressure. The aging process causes deterioration of the dermal elements surrounding the follicle. These changes are manifested by internal collapse of supporting skin structure and expansion of the follicular canal, resulting in pore dilation and greater visibility on the skin surface. The visual appearance of skin pores also partially depends upon the texture of surrounding surfaces. Rough skin scatters light in a manner which emphasizes openings on the skin surface, so pores appear larger.
Current treatments for enlarged pores are directed primarily to cleaning the skin to facilitate sebum and debris removal. Frequent washing is recommended for persons with oily skin, and washing with skin cleaners containing hydrating agents for persons with normal and dry skin. Sebum production is commonly curbed using drying agents such as alcohol and benzoyl peroxide.
It would be desirable to have alternative treatments for reducing skin pore size and improving overall skin appearance, particularly compositions that physically contract pores rather than just clean them.